Researchers at Shanghai University create tri-layered artificial blood vessels for the first time
By combining micro-imprinting and electro-spinning techniques, researchers at Shanghai University’s Rapid Manufacturing Engineering Center have developed a vascular graft composed of three layers for the first time. This tri-layered composite has allowed researchers to utilize separate materials that respectively possess mechanical strength and promote new cell growth - a significant problem for existing vascular grafts that have only consisted of a single or double layer.
Vascular grafts are surgically attached to an obstructed or otherwise unhealthy blood vessel to permanently redirect blood flow, such as in coronary bypass surgery. Traditional grafts work by repurposing existing vessels from the patient’s own body or from a suitable donor. However, these sources are often insufficient for a patient’s needs because of the limited supply in a patient’s body, and may be afflicted by the same underlying conditions that necessitate the graft in the first place. Accordingly, there has been a great deal of research towards developing synthetic vessels that can mimic natural ones, allowing new cells to grow around them and then degrade away, thereby creating new vessels.
"The composite vascular grafts could be better candidates for blood vessel repair," said Yuanyuan Liu, an associate professor at the Rapid Manufacturing Engineering Center. Liu’s team had previously worked with bone scaffolds, which are used to repair bone defects, before turning their attention to cardiovascular disease, and thus vascular grafts. They describe their current research in the journal AIP Advances, from AIP Publishing.
As a rule, surrogate scaffolds need to mimic the natural vasculature of their targeted tissue as much as possible. For blood vessel surrogates, this structural mimicry can be fabricated by electrospinning, a process which uses an electrical charge to draw liquid inputs – here a mixture of chitosan and polyvinyl alcohol – into incredibly fine fibers. Electrospinning also allows for a high surface-to-volume ratio of nanofibers, providing ample space for host cells to grow and connect. These components all naturally degrade within six months to a year, leaving behind a new, intact blood vessel.
The resulting structure, however, isn’t very rigid – the fly in the ointment for many previous models. To compensate for this, the researchers designed a three-layer model, in which the mixture was electrospun onto both sides of a microimprinted middle layer of poly-p-dioxanone, a biodegradable polymer commonly used in biomedical applications. The ends of this sheet were then folded and attached to make a tube-like vessel.
Liu and her team then seeded the scaffold with rat fibroblast cells, which are ideal candidates because of their ease of cultivation and quick growth rate, to test the scaffold’s efficacy in promoting cellular expansion and integration. The researchers found that the cells on these composite scaffolds proliferated quickly, likely due to the functional amino and hydroxyl groups introduced by the chitosan.
While a good deal of work remains before the prospect of human trials, Liu and her group are optimistic about the future of their research. Their next project is to test the implants in an animal model, to observe the structure’s efficacy with live vascular cells.
The article, "Composite Vascular Repair Grafts via Micro-imprinting and Electrospinning” is authored by Yuanyuan Liu, Ke Xiang, Haiping Chen, Yu Li and Qingxi Hu. It will appear in the journal AIP Advances on February 3, 2015 (DOI: 10.1063/1.4906571). After that date, it can be accessed at: http://scitation.aip.org/content/aip/journal/adva/5/4/10.1063/1.4906571
ABOUT THE JOURNAL
AIP Advances is a fully open access, online-only, peer-reviewed journal. It covers all areas of applied physical sciences. With its advanced web 2.0 functionality, the journal puts relevant content and discussion tools in the hands of the community to shape the direction of the physical sciences.
Jason Socrates Bardi
Jason Socrates Bardi | newswise
The stacked colour sensor
16.11.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt
Counterfeits and product piracy can be prevented by security features, such as printed 3-D microstructures
16.11.2017 | Karlsruher Institut für Technologie (KIT)
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
17.11.2017 | Physics and Astronomy
17.11.2017 | Health and Medicine
17.11.2017 | Studies and Analyses